This invention'relates to signs and bulletin board devices wherein the symbols, such as letters, are adapted to be removably or interchangeably assembled thereon, and it is the object of the invention to providea sign or bulletin board device of th1s character in which the symbols or letters are retained assembled upon the board by magnetic attraction, and to provide a device for this purpose which is simple and cheap in structure and eflicient in use.

In carrying out the invention I provide a plate of non-magnetic material preferably mounted in a frame, although thisis not labsolutel essential, and'inlay in said plate strips 0 magnetizable material in spaced and parallel relation with a surface of the strips exposed and flush with a surface of the plate, said strips being in the nature of pole pieces for magnets also carried by the plate with the poles of the respective magnets arranged in parallel and intimate contact with the pole pieces, symbols, such as letters, made of magnetizable material, or of nonmagnetic material having a magnetizable portion, being adapted to be as sembled upon the plate in contact with and bridging relation to the strips and retained assembled on the plate by magnetic attraction through the strips.

In the drawing accompanyin and form ing a part of this application, igure 1 is a front elevation of a sign or bulletin board embodying the invention.

Figure 2 is a rear elevation with a portion broken away to show an arrangement of the magnets in relation to the magnetizable strips.

Figure 3 is a view similar to Figure 2, of a portion of the device showing a modified arrangement of the magnets.

Figure at is a cross sectional view taken on the line H of Figure 2 looking in the direction of the arrows, and showing the same arranged with a support.

Figure 5 is an elevational view of a letter or symbol of magnetizable material to be as sembled upon the plate.

Figure 6 is a sectional view taken on the line 6-6 of Figure 5 looking in the direction of the arrow.

Figure 7 is an elevational view of a modified arrangement of a letter or symbol for assembling upon the plate; and

. Figure 8 is a cross sectional view taken on the line 8-8 of Figure 7 looking in the direction of the arrows.

In the embodiment of the invention illustrated there is provided a late 9 of nonmagnetic material. This p ate may be of wood or other suitable material, but is preferably made of a molded material, such as wax, bakelite, etc. This plate has inlaid therem in parallel and spaced relation strips in the form of bars 10 of magnetizable material, such as soft iron,'with a surface exposed and in flush relation with one surface, to constitute the front, of the plate, as shown in Figure 4. These strips are magnetized by means of magnets 11 carried by the plate, shown as permanent magnets of the horseshoe type. These magnets are arranged in sidewise intimate contact with'the strips 10 with the poles of the magnets arranged in parallel, as indicated by the characters N and S on the respective pole portions of the magnets. As shown in Figure 2, whichis the preferred form of the arrangement of the magnets, these magnets are arranged in pairs with the poles in contact and opposed relation, that is the north oles and south poles are op osed to each ot er. In the arrangement s own in Figure 3 the poles are in opposed relation to the bend of an adjacent magnet and spaced therefrom so that the attractive force of a magnet will not be dissipated and tend to act as an attractive force on an adjacent magnet. By this arrangement the magnetizable strips are adapted to serve as pole pieces for the respective magnets, the one strip being com mon to one pole, as the positive pole to the respective magnets, while the otherstrip is common to the other pole, as the negative pole of the magnets.

When the plate is made of wood or the like non-magnetic-material the magnets and strips are mounted in recesses arranged therein. However, when the plate is made of molded material they are molded directly into the material of the plate in embedded relation thereto and the magnets entirely surrounded by the material of the plate with the exception of the portions thereof in contact with the strips. Theplate is preferably mounted in a frame 12, although this is not absolutelyessential, as the plate itself may function as a sign or bulletin board without the use of a frame. To support the sign or bulletin board in a substantially perpendicular position or slightly inclined to the perpendicular it is arranged with what tached to the back of the plate.

Symbols, such as letters 14, are adapted to be assembled upon the plate and retained assembled thereon through the ma netic force transmitted to the strips 10 by t e magnets 11. For this purpose the symbols are made of magnetizable material, such as iron, as by stamping from a sheet, as shown in Figures 5 and 6. However, the symbols may be made of non-magnetic material, such as celluloid, pyralin, bakelite and the like and in order that they may be retained assembled upon the plate through magnetic attraction they are arranged with a portion of magnetizable material, preferably in the form of a backing plate of iron, as shown at 15 in Figures 7 and 8, and upon which the symbols are mounted. In the assembling of the symbols or letters upon the board they are-arranged so that they will bridge and be in contact with a pair of strips associated with a series ,of alined magnets.

While I have illustrated the invention as embodying a single pair of the magneti'zable which case in the assembling of the symbols upon the plate they may be arranged so that a portion thereof is in contact with one strip of a pair of strips associated with one row of magnets and a strip of an adjacent pair of strips in the series so that the symbols will bridge and be in contact with a strip of one pair of strips in contact with one pole of a row of magnets, such as the south pole, and with a strip of another pair of strips in contact with one pole, such as the north pole of an adjacent row of magnets. 1

It will be obvious that various modifications may be made in construction. and arrangement of parts, and portions of the invention may be used without others, without tion to the strips with one pole portion of the magnets in contact with one strip and the other pole portion in contact with another strip and the magnets arranged with the poles in parallel.

3. A sign as claimed in claim 1, wherein the magnets are arranged with the positive pole of each magnet in contact with one strip and the negative pole of each magnet in contact with another strip, and the plate is formed of molded material with the magnets and strips embedded therein and having one face of the strip exposed and in flush relation with a surface of the plate.

4:. In a sign as claimed in claim 1, symbols assembled upon the plate in contact with and bridging the strips and adapted to be retained assembled on the plate by magnetic attraction through the strips.

5. In a sign, a plate of non-magnetic material, strips of magnetizable material inlaid in spaced and parallel relation in the plate and having one face exposed and flush with the surface of the plate, magnets carried by the plate arranged with the poles in parallel and a pole in contact with one strip'and the other pole in contact with the other strip whereby the strips are adapted to serve as pole pieces for the magnets, and symbols adapted to be assembled upon the plate in contact with and bridging the strips and retained assembled on the plate by magnetic attraction through the strips.

Signed at the city of New York, in the county of New York and State of New York this 7th day of November, 1927.